1. Field of the Invention
The present invention relates to a system and method for measuring viewing zone characteristics of an autostereoscopic three-dimensional (3D) image display device, and more particularly, to a system and method for measuring viewing zone characteristics of an autostereoscopic 3D image display device which may efficiently determine a precise optimum viewing distance (OVD) by analyzing ray tracing results from at least one viewpoint image of some local areas of the autostereoscopic 3D image display device, and determine a position error range of viewpoint images formed from mutually different areas of the 3D image display device.
2. Discussion of Related Art
The optical property of a multi-view three-dimensional (3D) image display device using a parallax barrier is generally slightly different from designed values. The representative values among the designed values of the multi-view 3D image display device are an optimum viewing distance (OVD) and a viewpoint distance (VPD) in OVD.
In order to estimate an image quality of the multi-view 3D image display device, the OVD is usually measured and the optical characteristics such as crosstalk and luminance uniformity are evaluated in the measured OVD. Various evaluation methods of the multi-view 3D image display device have been presented. However, a decision method of position error of viewpoint images formed from the entire 3D display area and a precise measurement method of OVD are not presented until now.
FIG. 1 is a conceptual diagram illustrating a 3D image display device using a conventional parallax barrier.
Referring to FIG. 1, the 3D image display device using the parallax barrier according to the prior art roughly includes a display unit 10, a parallax barrier 20 disposed on a front side of the display unit 10 to be spaced apart from the display unit 10 by a predetermined distance, and the like. Here, the display unit 10 may use a general liquid crystal display (LCD) panel.
The parallax barrier 20 is formed in such a manner that a slit type aperture through which light emitted from the display unit 10 is transmitted and a barrier for blocking light are repeatedly arranged. The slant parallax barrier 20 is used to maintain uniform color characteristics at each viewing zone and allocate the reduced resolution to longitudinal and transverse directions of the display unit 10. In this instance, the slanted angle of the parallax barrier 20 may be, for example, tan−1(⅓)=18.435 degrees.
Meanwhile, the relationships between variables of n-view 3D display with the parallax barrier 20 may be represented as Relation Equations shown on a lower side of FIG. 1. Here, WP is a unit pixel size or unit subpixel size, WPB_S and TPB are respectively a size and period of the slit type aperture of the parallax barrier 20, d is a distance between the display unit 10 and the parallax barrier 20, and DVP is a viewpoint distance at OVD. Almost all methods to measure the optical characteristics of multi-view 3D display use angular properties of viewpoint images from a local spot of the display unit 10.
However, these measurement methods are practically different from an observer's situation seeing 3D images, because luminance of viewpoint images formed from the entire 3D display area affects the observer and a condition (for example, a gap) between the display panel and the parallax barrier at the entire 3D display area is not generally uniform.